Hey guys I'm new to this site so bear with me. I recently bought a 97 cherokee and have some tranny problems. so when ever i'm crusing at a set speed my tranny shifts in and out of overdrive. i doesnt matter what speed im at as long as im at a steady one it does it. it also only seems to do when it is warmed driving and have been driving a mile or more. i'm not sure whether this is related to it or not but it also slams into gear when ever i shift into drive or reverse. i've been to a tranny shop already and they said its got a toyota trans in it and usually never have problems they said they thought it was the tps sensor. so i replaced it right away. no improvement. any advice would be greatly appreciated thanks

 

Have you tried adjusting the throttle valve cable?
https://www.cherokeeforum.com/f2/free-quick-fix-41821/

Not technically a "toyota" transmission, it was built by Aisin-Warner, the majority shareholder is (or was) Toyota and they supply a lot of trannys to Toyota, but it's a separate entity. They also supply certain transmissions to Honda, Suzuki, Isuzu, GM, Ford, Porsche....

 

I haven't tried that yet. I'll do I today but do you think that will solve the overdrive problem

 

Didn't work still doing the same thing

 

Just a guess.. you might check that your brake light switch is functioning and adjusted correctly. It not only turns on your brake lights, it also sends a signal to the torque converter (unlocks it) and if I recall correctly, affects the OD. Not sure about that tho. Are you sure it's going in and out of OD and not the Torque converter locking/unlocking? When the TC goes on/off your engine speed will change by a few hundred rpms.. Again, just a guess.

 

Idk I mean does pretty much what you said it drops back and forth between rpms. I feels like its shift back and forth between gear it also shifts harsh when accelerating and deccelerating. I really don't know much about automatic tranmissions and how they work

 

Did you adjust the TV cable? If so, did it ratchet into position as it 'self adjusted'?
I don't know what transmission you have.. Does your shifter indicator have (1-2) (3) and (D) with a circle around the D? Try driving around in position 3.. Then post back how it shifts/runs in 3. In 3, it should drive normally, but won't shift into overdrive. If it seems all better, then you can be sure it's something to do with the over drive. Let us know. (if it has some sort of push button for overdrive, take it out of OD and try it that way)

 

If it's slamming into drive and reverse and you are *certain* the TV cable is adjusted properly AND you are certain it's the transmission slamming and not loose/worn driveline components, I'd suspect a dirty or obstructed valve body or accumulator(s).
What does the trans fluid look/smell like? How does it shift between gears?
I'd try driving it manually with the TCU disconnected and see if it still slams into gear.

The overdrive dropping out- in addition to the brake switch, might check over and clean your NSS. One of it's functions is to supply range selector information, which *might* be relevant to Overdrive operation.

 

A low tranny fluid level will give this exact same syptom. Guess how I know?

Just in case you don't know, to check auto tranny fluid, give your Jeep a little drive to warm the tranny fluid (about 10+ minutes should do it) - DO NOT TURN IT OFF, but once you've done your drive, sit there with the engine idling and foot on the brake and move the shifter through each of the shirter positions for a few seconds each. Once done, return the shifter to PARK and leave the engine idling. Now pop the hood and check your fluid level WITH THE ENGINE STILL RUNNING AND THE SHIFTER IN PARK (don't run yourself over please).

 

adjst thetv cable
I do this about every 2 months & it works
take about a minute

 

Drove it around in only 3 not drive and it did the same thing so I guess its not the over drive. I checked the tranny fluid its at the right level its light brown and smells a little funky. I did adjust the TV cable making sure it ratchet into place. When I did that it made the shifts worse as in harder up and down shifts when accelerating and deccelerating. I didn't check the brake light switch or disconnect the tcu yet

 

bUMP

 

I thought you were supposed to check it in neutral? Or is that just me?

 

I disconnected the TCU and it doesnt slam as bad into gear. i think it worn driveline part. As for the Torque Converter locking and unlocking that stopped after disconnecting it. so where should i go from there. i tried to adjust the brake light switch by pressing the pedal all the way down and trying to plug the plunger all the way out then pulling the pedal back in listening for the ratcheting noise but the plunger didnt move. is there something else i have to do to get the plunger to come out or is it all the way out. what am i looking for when i check the NSS and can that be adjusted as well? I'm not really sure what else i should check

 

My Saab has an Aisin-Warner AW4 FWD trans So both my cars has an AW4(completely different trans i know, but cool nonetheless)
wish i had any advice for you man, but everything i was gonna say has already been said.